Particles from volcanic eruption worsened respiratory conditions
Six years ago, there was a marked rise in respiratory diseases among Reykjavik residents during one of Iceland's biggest volcanic eruptions on record, according to new research findings, to which University of Gothenburg scientists contributed. The adverse health effects increased most when the sulfur dioxide emissions returned in the form of sulfate aerosol deposition.
The present research is based on air quality data and health care records in Reykjavik during the major flood lava eruption of 2014–15 in the Icelandic lava field Holuhraun from a fissure near the Barbarbunga (Bárðarbunga) volcano. The eruption spread 11 million tons of sulfur oxide over a massive area.
The eruption lasted for six months. Reykjavik residents were repeatedly exposed to sulfur dioxide (SO2) emissions in the form of gas and deposition of airborne particles known as sulfate aerosols.
Increased need for primary care and asthma medication
Hanne Krage Carlsen, a researcher in occupational and environmental medicine at Sahlgrenska Academy, University of Gothenburg, is among those primarily responsible for the current scientific publication in the journal Nature Communications on health effects in Reykjavik following the volcanic eruption.
“This is the first time health effects in a large population have been studied after a huge volcanic eruption. We see that high levels of sulfur dioxide, above all, boosted primary care and asthma medication needs and that there was a further increase in respiratory diseases when the gas cloud matured above the Atlantic and then returned, depositing particles,” says Krage Carlsen, who held a postdoctoral research position at the University of Iceland when the study began.
The study shows that exposure to the fine particles from the mature volcanic cloud led to 11 per cent more residents in Reykjavik contacting primary-care services to seek help for respiratory problems. The most significant increase was among older inhabitants, whose primary-care contracts rose by 28 per cent. In terms of prescriptions for asthma medicine, the biggest increase was observed among children and adolescents: these drugs were prescribed for 25 per cent more residents under the age of 18. There was a 13 per cent increase in such prescriptions among adults and older people.
First gas, then particles
During the eruption, sulfur dioxide gas clouds formed and intermittently reached Reykjavik, 250 km from the eruption site. The plume drifted across the North Atlantic toward Europe, and when the gas clouds returned, their contents had, through a chemical process, matured from gas to aerosols (fine airborne particles). Volcanologist Dr Evgenia Ilyinskaya, a researcher at the University of Leeds and co-author of the present publication in Nature Communications, has described the process.
“Our research shows that during prolonged eruptions such as the one at Holuhraun, both young and mature volcanic clouds can circulate simultaneously, which exacerbates the harmful health effects on inhabitants of volcanic regions,” Ilyinskaya says.
Aerosols found in mature volcanic plumes are thought to be capable of penetrating and damaging the lungs and causing asthma attacks, for example. The chemical maturation process in the Icelandic volcanic plume reduced the concentration of SO2. Since its level was below the threshold value considered harmful, no warnings were issued to Reykjavik’s residents.
The present study in Nature Communications highlights the need for decision-making authorities to be prepared to inform the population in the days immediately following volcanic eruptions about the risk of health problems associated with returning emissions.